#include <iostream>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <string.h>

void ChildWrite(int wfd)
{
    char buffer[1024];
    int cnt = 0;
    while(true)
    {
        snprintf(buffer, sizeof(buffer), "I am child, pid: %d, cnt: %d\n", getpid(), cnt++);
        write(wfd, buffer, strlen(buffer));
        sleep(1);
    }
}

void FatherRead(int rfd)
{
    char buffer[1024];
    while(true)
    {
        buffer[0] = 0;
        ssize_t n = read(rfd, buffer, sizeof(buffer) - 1);
        if(n > 0)
        {
            buffer[n] = 0;
            std::cout << "child say:" << buffer << std::endl;
        }
    }
}

int main()
{
    //1.创建管道
    int fds[2] = { 0 };//fd[0]读端，fd[1]写端
    int n = pipe(fds);
    if(n < 0)
    {
        std::cerr << "pipe error" << std::endl;
        return 1;
    }
    std::cout << "fds[0]" << fds[0] << '\n';
    std::cout << "fds[1]" << fds[1] << '\n';

    //2.创建子进程
    pid_t id = fork();
    if(id == 0)
    {
        close(fds[0]);
        ChildWrite(fds[1]);
        close(fds[1]);
        exit(0);
    }

    close(fds[1]);
    FatherRead(fds[0]);
    close(fds[0]);

    waitpid(id, nullptr, 0);

    return 0;
}